The present disclosure relates generally to electrical adapters and methods related to such adapters. More particularly, the present disclosure pertains to adapters for packaged integrated circuit devices, e.g., ball grid array packages.
Certain types of integrated circuit packages are becoming increasingly popular due to their occupancy area efficiency. In other words, they occupy less area on a target board on which they are mounted while providing a high density of contact terminals. For example, one such high density package type is a ball grid array package (e.g., a micro ball grid array package). Generally, such packages contain an integrated circuit having its die bond pads electrically connected to respective conductive contact elements (e.g., spheres/balls) that are distributed on a surface of the package (e.g., the bottom surface of the package, for example, in an array).
A target printed circuit board upon which the package is to be mounted typically has formed on its surface a corresponding array of conductive pads which are aligned with the conductive contact elements of the packaged device for electrically mounting the package on the target board. The target board typically includes other conductive traces and elements which lead from the array of conductive pads used for mounting the package to other circuitry on the board for connecting various components mounted thereon. To mount such a package to a target board, for example, the package may be positioned with the contact elements thereof adjacent to the corresponding array of conductive pads on the target board and, for example, the resulting structure may be heated until solder melts and fuses the contact elements of the package to the conductive pads of the target board.
Such area efficient packaging, e.g., micro ball grid array packages, provides a high density of terminals at a very low cost. Also, this packaging provides for limited lead lengths (e.g., short leads). The limited lead lengths may reduce the risk of damage to such leads of the package, may provide for higher speed product, etc.
Generally, circuit boards and/or components mounted thereon are tested by designers as the circuit boards are being developed. For example, for a designer to test a circuit board and/or a package mounted thereon, the designer must first electrically connect the package to the target circuit board.
As described herein, this may include mounting the package on the target board and heating to fuse the contact elements of the package to the conductive pads of the target board. Therefore, the package may be prevented from being used again. It is desirable for various reasons to use package adapters for mounting the packages and reuse such packages after testing. For example, such device packages may be relatively expensive. Further, for example, once attached, the contacts may not be accessible for testing. In addition, it is often difficult to rework the circuit board with the packages soldered thereon.
Various adapters are available to electrically connect a package to a target printed circuit board without requiring that the contact elements on the package be fused to the target board. However, the high density of terminals for certain packages, e.g., micro ball grid array packages, leads to various interconnect problems for adapters being used with such packages. For example, alignment of the contact elements of the packaged device to the contact pads of the target board may be problematic when an electrical adapter is used. Further, providing effective contact with minimal adaptive structure may be difficult. Various adapters have been described for electrically connecting high density packaged devices to a target printed circuit board, such as, for example, U.S. Pat. No. 6,877,993 to Palaniappa et al., issued 12 Apr. 2005, entitled “Packaged Device Adapter Assembly with Alignment Structure and Methods Regarding Same,” and U.S. Pat. No. 6,394,820 to Palaniappa et al., issued 28 May 2002, entitled “Packaged Device Adapter Assembly and Mounting Apparatus,” describe adapter apparatus that use a conductive elastomer layer to provide electrical contact.